Enraged over suspicions her 4-year-old daughter had been molested, a Banning woman and her fiance plotted to take justice into their own hands and shot a man in the head, authorities believe.

But the next day, a medical examination found no evidence the girl had been sexually assaulted, according to court records.

The fiance soon ended up in prison for domestic violence. There, court records say, he referenced a newspaper article about the shooting and told a fellow inmate, “That was me … I had to kill this dude.”

Brian Thomas Matheis and Amy Lou Daniel, both 30, are now charged with murder in the shooting of Banning resident Joshua Lee Fredieu.

Fredieu was found at 10:55 p.m. Aug. 22, 2012, with a gunshot behind his ear inside a car that had crashed by railroad tracks near South Florida and South Plaza streets in Banning.

About two months later — following Matheis’ conviction for hitting Daniel while they were on drugs — Banning detectives were notified that an inmate in custody with Matheis had information about the killing, according to an affidavit filed seeking a warrant for Matheis’ arrest.

The morning of Fredieu’s death, Daniel came over to pick up her daughter, who’d had a sleepover with Fredieu’s daughter, according to the affidavit.

Everyone at Fredieu’s house had still been sleeping, so he scrambled to get dressed and offered to give Daniel and the girl a ride home, police wrote.

Matheis told the other inmate that the girl was naked when Daniel picked her up.

That morning, Daniel was tending to the girl as she was having trouble urinating, an unidentified witness told police. The witness overheard Daniel trying to coach her daughter into saying Fredieu molested her, but the girl said he didn’t touch her, according to court records.

Matheis said Daniel plotted to kill Fredieu, according to court records. They asked Fredieu to give Matheis a ride to pick up milk. While in the car, Matheis pulled a gun and said, “I know what you did to my daughter,” before shooting him in the back of the head, according to court records. Daniel’s family noted Matheis is not the girl’s biological father.

The next day, Matheis and Daniel took the girl for a sexual assault exam, court records say. But no evidence of molestation was found, and the couple left while being interviewed by child protective services.

The couple fled to Minnesota after the killing, but soon returned to Banning.

After a police investigation, murder charges were filed June 25.

Daniel was arrested Aug. 13 at Murray and Hay streets in Banning and booked into the Robert Presley Detention Center in Riverside, with bail set at $1 million.

Matheis was arrested on the homicide charge at the state prison in San Luis Obispo, where he is serving his nine-year sentence for domestic violence. He has not yet been returned to Riverside County.

Daniel is set to be arraigned Thursday, Aug. 22, and Matheis is scheduled to be arraigned Sept. 11.